On August 13, the FAA held 18 airports in the United States under 27 delay programs. The hardest hit airport was Chicago O’Hare International (ORD), which experienced a ground stop lasting 21 hours and 40 minutes with staffing issues and thunderstorms cited as reasons. The peak delay in the network reached 102 minutes on average, with a maximum observed peak delay of 312 minutes.
Duration and Types of Delay Programs by Airport
The FAA imposed six ground stop programs on various airports. Ground stops hold departures bound for an airport at their origin to manage arrivals. Chicago O’Hare’s ground stop, attributed to staffing shortages and thunderstorms, was observed from 00:40 UTC to 22:20 UTC. Harry Reid International (LAS) and Denver International (DEN) also had ground stops due to thunderstorms lasting 20 hours and 1 hour 40 minutes respectively. Phoenix Sky Harbor (PHX), Orlando International (MCO), and Seattle-Tacoma (SEA) had shorter ground stops ranging from 20 minutes to 1 hour 20 minutes for thunderstorms or low visibility.
Ground delay programs, which meter arrivals
by assigning later departure times, numbered eight across the sample. The longest ground delay program was at LAS lasting 22 hours and 20 minutes with thunderstorms as the stated cause, and a peak average delay of 102 minutes with peaks reaching 312 minutes. Denver International also had a ground delay program due to thunderstorms lasting 2 hours with peak average delays of 94 minutes.
Other airports under ground delay programs included San Diego International (SAN) with a 21-hour program caused by airport volume, Chicago O’Hare with a 21-hour 20-minute program citing a disabled aircraft on the runway and other reasons,
and Newark Liberty International (EWR) with 2-hour ground delays attributed to other causes. San Francisco International (SFO) had a 5-hour program caused by low ceilings, while YUL and YVR both had shorter ground delay programs citing other reasons.
| Airport | FAA programme | Cause | Peak average delay | In force (UTC) |
|---|---|---|---|---|
| Chicago O’Hare International (ORD) | Ground Stop Programs | STAFFING; thunderstorms | – | 00:40 to 22:20 (21 hours 40 minutes) |
| Harry Reid International (LAS) | Ground Stop Programs | thunderstorms | – | 02:00 to 22:00 (20 hours) |
| Denver International (DEN) | Ground Stop Programs | thunderstorms | – | 01:20 to 03:00 (1 hour 40 minutes) |
| Phoenix Sky Harbor International (PHX) | Ground Stop Programs | thunderstorms | – | 01:20 to 02:40 (1 hour 20 minutes) |
| Orlando International (MCO) | Ground Stop Programs | thunderstorms | – | 21:40 to 22:20 (40 minutes) |
| Seattle-Tacoma International (SEA) | Ground Stop Programs | low visibility | – | 17:00 to 17:20 (20 minutes) |
| Harry Reid International (LAS) | Ground Delay Programs | thunderstorms | 102 min | 00:00 to 22:20 (22 hours 20 minutes) |
| Denver International (DEN) | Ground Delay Programs | thunderstorms | 94 min | 20:20 to 22:20 (2 hours) |
| YUL | Ground Delay Programs | other | 78 min | 00:00 to 00:00 (20 minutes) |
| San Francisco International (SFO) | Ground Delay Programs | low ceilings | 39 min | 13:00 to 18:00 (5 hours) |
| Newark Liberty International (EWR) | Ground Delay Programs | other | 38 min | 20:20 to 22:20 (2 hours) |
| San Diego International (SAN) | Ground Delay Programs | airport volume | 34 min | 00:00 to 21:00 (21 hours) |
| Chicago O’Hare International (ORD) | Ground Delay Programs | other; disabled aircraft on the runway | 32 min | 01:00 to 22:20 (21 hours 20 minutes) |
| YVR | Ground Delay Programs | other | 22 min | 00:00 to 04:40 (4 hours 40 minutes) |
Thunderstorms and Airport Volume Were Leading Causes
The top causes for delay programs included thunderstorms with 51 mentions, airport volume at 32, and Traffic Management Initiatives related to weather (TM Initiatives:MIT:WX) at 30. Other causes accounted for 28 mentions, with low ceilings causing 16 programs. Thunderstorms were the primary driver of ground stop programs at ORD, LAS, DEN, PHX, and MCO. Airport volume mainly contributed to the long ground
delay program at SAN. The FAA cited staffing, disabled aircraft on the runway, low visibility, and other operational issues across affected airports.
Delay Trends Compared to Previous Days
Compared to the previous day, August 12, the number of airports affected by delay programs decreased slightly from 19 to 18, while the total number of programs went down from 32 to 27. When compared to a seven-day average of 22 airports affected, today’s total remains below average. The peak delay figures on August 13 do not represent the worst in the tracking window. This data shows a modest decline in the delay program activity across the United
States.
Methodology. travelandtournews.com samples the FAA’s National Airspace System status feed every 20 minutes throughout the US operating day and aggregates the result. This report is built from 68 samples taken between 00:00 and 22:20 UTC on 2026-08-13. Durations are the observed window between the first and last sample in which a programme was in force, so a programme’s true length may be slightly longer than shown. Ground stops, ground delay programmes, airport closures and general delays are all published by the FAA in real time; the daily aggregation is ours.
